Mold assembly

Abstract

A mold assembly has two mold half shells each having an outer and inner wall for defining the shape of a container to be formed. Two mold half carriers each have an inner wall overlaying and spaced from a corresponding mold shell outer wall for supporting the shells in the assembly. At least one insulating pad is sandwiched between the inner wall and the corresponding outer wall and is secured to one of the inner wall and the outer wall. The pad supports the outer wall in non-contacting and buffering relation relative the carrier inner wall. Each pad may be secured in a recessed seat in the respective wall. Pads may be secured in recessed seats having a depth less than the thickness of the pad. Pads absorb mold operational forces to reduce wear, reduce conduction from shell to carrier and facilitate the use of different-sized shells with one carrier.

Description

FIELD OF THE INVENTION[0001]The present invention relates to molds for making containers, and more particularly to molds having shell inserts carried by mold carriers where insulative pads are located between the outer walls of the shell and the inner walls of the carriers.DESCRIPTION OF THE RELATED ART[0002]Mold assemblies having two side mold parts and a base mold part are commonly used in the formation of plastic containers such as, for example, biaxially-oriented PET (polyethylene terephthalate) beverage bottles. The side mold parts may comprise a unitary half-part, multiple half-parts or a unitary shell half insert.[0003]In hot fill applications such as, for example, formation of juice containers that are subsequently filled with hot juices, it is important to maintain elevated temperature levels at the forming surface where the mold face contacts the plastic of the container to form a plastic container capable of withstanding hot filling temperatures of liquids subsequently fi...

AI Technical Summary

Benefits of technology

[0008]The placement of the insulating pads spaces the carrier inner wall and the shell outer wall. The non-contacting relationship between the shell outer walls and the carrier inner walls prevents unnecessary wear on the mold carrier and reduces damage to the mold assembly. The pads also provide a buffer between the shell outer walls and the carrier inner walls. With the pads in place, the mold shell is supported without direct contact between outer wall of the mold shell and the inner wall of the carrier. Accordingly, the pads absorb the mechanical forces associated with the operation of the mold assembly. Moreover, thermal conducting contact between the shell outer walls and the carrier inner walls is prevented. In this manner, heat exchange between the shell and the carrier is buffered and therefore substantially reduced.

[0010]In an alternative embodiment of the present invention, a plurality of insulating pads is secured to the one of the carrier inner wall and the corresponding shell outer wall. The insulating pads are sized and spaced to provide a uniform mechanical and thermal load distribution between the inner walls of the mold half carrier and the corresponding shell outer wall. The insulating pads help to contain the heat / cooling supplied to the mold assembly. The pads may be spaced for defining thermal air buffering zones between the pads. The air buffering zones reduce heat transfer from the shell to the carrier.

Problems solved by technology

The problem with present molds is that heat dissipates away from the mold face to the outer walls of the mold requiring greater heat energy to maintain the elevated predetermined temperature.

Such heat dissipation may cause the outer walls of the mold to heat to a temperature which may be harmful to nearby components or to technicians who may come into contact with the heated mold outer wall.

In hot or cold fill mold assemblies where the mold shells are supported in direct contact with mold carriers, regular operation of the mold assembly may cause mechanical wear where there is contact between inner surfaces of the mold carriers and outer surfaces of the mold shells.

This wear may cause unnecessary mold damage and may hasten the need for expensive replacement of the carrier.

Moreover, since the mold shells are supported in direct contact by the carriers, the mold carrier is not adaptable to support a mold shell of a different diameter or size without changing the size of the carrier to suit the diameter of the new shell.

Another concern associated with contact between the mold half carriers and the mold half shells in mold assemblies is wear between the parts.

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